Right cylinder blue smoke on an R80/7. Oh dear...

Discussion in 'Airheads' started by Blackburn Buccaneer, Feb 27, 2019.

  1. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

    Joined:
    Aug 5, 2018
    Oddometer:
    162
    Location:
    North Sea rim
    All your advice is being written down in a Word file as a sort of doctrine to use when we'll get the back back out again :ear

    I corrected the gaskets after the pic, they are sealant free though. New ones are on order, because the left side one has a nick in it.

    My dad has some Molykote A (final drive additive) left over from a Guzzi project he did last year, would that suffice? Trans rebuild should set us back 395 euros, not cheap but hey I don't want it to explode on us riding it.

    Duly noted, will correct that when the new intake rubbers arrive, thanks! The (non-smoking) Left side carb is at much less of an angle, that might explain why balancing the carbs in their current state was impossible lol.

    This one has more of an accidental slant ;)

    Cheers for the insights! It is running rich in the right side and right now it doesn't need choke to start, so that says something about the state of the carb tune. I'm still waiting for new intake rubbers to replace the old cracked ones before I can really tweak the carbs to a better level. I wouldn't be surprised if it was the carbs all along, those bad boys can cause a lot of trouble. I ran it without the right side carb connected to the airbox and it still smoked under load, but we'll still check out the vent when the weather improves again.

    I thing my dad is learning the most here, he was swearing on the dual Bing setup, because he's used to a lone Amal connected to a British single. "These fuckers are hard to get right" :D I have some experience tuning Bings from my R45, the single biggest improvement I got with that one was new rubbers and new cables. Never had that one smoke on me, but it did smell like a refinery before overhaul.
    #41
  2. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

    Joined:
    Aug 5, 2018
    Oddometer:
    162
    Location:
    North Sea rim
    I'm saving the ring replacement till last. A wise old man once told me nothing is worth shit without correctly tuned carbs. It might also save us some coin ;)
    #42
    nk14zp and Richarde1605 like this.
  3. Jim Day

    Jim Day full manic mechanic

    Joined:
    Mar 14, 2012
    Oddometer:
    5,332
    Location:
    So. Cal.
    Well you already have a partial solution, that 20W50 should slow down the oil consumption :D
    #43
    nk14zp and Blackburn Buccaneer like this.
  4. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

    Joined:
    Aug 5, 2018
    Oddometer:
    162
    Location:
    North Sea rim
    Oil changes are satisfying. It already subsided the smoke quite a bit! It wasn't using too much oil to start with though :hmmmmm
    #44
    Jim Day likes this.
  5. Plaka

    Plaka Brevis illi vita est

    Joined:
    Jun 19, 2010
    Oddometer:
    6,074
    Location:
    .
    https://www.ulbrich-group.com/molykote-a

    But the LubroMoly stuff is German.
    #45
    Blackburn Buccaneer likes this.
  6. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

    Joined:
    Aug 5, 2018
    Oddometer:
    162
    Location:
    North Sea rim
    #46
  7. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

    Joined:
    Aug 5, 2018
    Oddometer:
    162
    Location:
    North Sea rim
    Alright so quick update; my dad and I had some spare time and put on new intake rubbers, Hoske replica pipes and some new cables for the clutch and throttle and the smoke isn't really there anymore. At least it wasn't around during and after my first test ride, so I'll have to confirm this some more after my midterms next week are done. The slanted carbs were turned right side up as well and it runs a lot better too. The only weird thing is that it shoots some black smoke out of the right exhaust sometimes, so I'll probably have to adjust the mixture some more because of the new cans and the lack of false air being sucked it. Could also be the some of the WD-40 left in the exhaust from when I was cleaning it.

    Idle is good too, still hangs up sometimes and it's not the advance mechanism, checked that ant it's fine. Probably the terribly tuned carbs, which I can new finally set properly with the new rubber.

    Let's see if stays smoke free. For now, some pics:

    [​IMG]

    [​IMG]

    Also put some Euro bars on there for good measure.
    #47
  8. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

    Joined:
    Aug 5, 2018
    Oddometer:
    162
    Location:
    North Sea rim
    Well cock

    [​IMG]

    Looks like both sides now, this is after a 15 min drive. I'm gonna start researching pulling the jugs and collecting the parts and tools needed. What would you guys advise me on the following points:

    - Should I get the cylinders checked out and honed by shop when they're off before installing new rings?
    - I've done a few simple Japanese engines below 250cc before and I never needed a ring compressor, but I want to buy one for this project, is that advisable?
    - Any thing else I should keep in mind or definitely check out?

    Cheers!
    #48
  9. Texer

    Texer Been here awhile Supporter

    Joined:
    Jun 5, 2015
    Oddometer:
    574
    Location:
    Seattle
    I’d Check out Duane Ausherman’s site regarding ring compression; his advice on using the cylinder bevel has worked for me. http://w6rec.com/duane/bmw/piston/ringtool.htm
    #49
    Blackburn Buccaneer likes this.
  10. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

    Joined:
    Aug 5, 2018
    Oddometer:
    162
    Location:
    North Sea rim
    Nice, great site:

    Thanks for that!
    #50
    Texer likes this.
  11. Piggdekk

    Piggdekk love speed, hate rush

    Joined:
    Aug 14, 2015
    Oddometer:
    603
    Location:
    Barcelona
    One should ALWAYS measure cylinders and pistons, no matter how they look. Measuremente would tell You what needs doing. I don't believe airheads are an exception to this. A decent machine shop will measure and advice.
    You don't need a ring compression tool, but You can also buy a pipe clamp (not sure how they're called in english, I mean same as the ones on the manifolds, just larger) to help you fit the rings.
    luca
    #51
  12. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

    Joined:
    Aug 5, 2018
    Oddometer:
    162
    Location:
    North Sea rim
    Alright, noted. Thanks!
    #52
  13. bpeckm

    bpeckm Grin! Supporter

    Joined:
    Apr 2, 2008
    Oddometer:
    7,874
    Location:
    Road Island
    Without going back through the thread.... have you done a leak-down test? Chances are good that it's something in the heads rather than the rings, and a leak-down test would help you decipher what's going on. I don't know that I would rush into a ring-replacement without some other testing. Just sayin'.....
    #53
    Blackburn Buccaneer likes this.
  14. nobbylon

    nobbylon Long timer

    Joined:
    Aug 13, 2012
    Oddometer:
    1,039
    where in NL are you? If you are close by Leiden and need a helping hand.....
    #54
    Blackburn Buccaneer likes this.
  15. cycleman2

    cycleman2 Long timer

    Joined:
    Jan 18, 2010
    Oddometer:
    1,433
    Location:
    Alberta, Canada
    I'm still not sold that the carbs are right. When you go from no smoke to smoke, after you've been messing with the carbs, that is where I would look first. Retrace your steps and go back to where you were before you made the last change. You obviously changed something.

    Make sure the choke/enrichener's are coming all the way off and that the levers are pointed in the right direction. The carbs are not hard to get right, but you have to make sure they are really clean, floats adjusted properly ( and if old original ) they should be replaced. Any of the wear items, O rings etc should be replaced, and set everything to stock settings. The engine has to be fully warmed up, take for a ride for 10 minutes or so, before doing any carb adjustments.

    Some hints of problem areas. Hanging idle - can indicate a lean condition possibly an air leak or maybe the enricheners are not working properly, not enough slack in a cable and that sort of thing. Mixture screw - If turning this in or out doesn't make any difference in the idle on fully warmed engine, suspect that the O ring or the actual screw maybe damaged ( replace the O ring first and see what happens ) or the idle circuit is still dirty. Before doing any sync's make sure the throttle cables have slack.

    It has been my experience with these carbs that the stock settings, with possibly a slightly richer needle jet for the newer models, work the best on a fully warmed engine. Not counting altitude. Use the settings in the bing book for the mixture screw, and then set the throttle screw, by turning it out until you can just get a piece of paper to pass through the contact points on the throttle screw, with a slight drag, remove the paper and then turn the throttle screw in 1 full turn. ( this opens the throttle plates to allow enough air into the cylinder to let the engine start) and sets the base line for both carbs. Any adjustments to either of these screws should be in very small amounts, use the thickness of the screwdriver slot and only turn the screws in or out that much, and then listen, check idle, sync etc, before you make any futher adjustments.

    When you have got everything set, then take the bike for a ride and take your screwdriver with you. Once the engine is fully warmed up, no choke, you are looking for an idle around 1000 rpm on a completely warmed engine. You may have to tweak the throttle screw ( equally on both sides to get the idle just right ). You shouldn't have to adjust the mixture screw. The next day, on a cold engine, use full choke/enrichner to start it and then gradually take the choke off. You will likely notice that the engine is idling fine, but slower than the day before. Don't adjust the carbs, take it for a ride and it should go back up to the normal idle when it gets warmed up.

    Another thing to check on older airheads, is that the sparkplug leads are in good shape. I had a case where a fellow was complaining about bad idle, cutting out and then running fine when he gave it more throttle. We chased the carb adjustments for a few minutes and nothing really changed so I took the plug wires off the spark plugs and took the wire out of the plug end. It was green ( corrosion and obviously wasn't making good contact ). I cut a 1/4" off the wire end to get good clean material, put the plug wire back together and the bike ran perfectly. So it is possible that your problem may not only be carb issues.
    #55
    Blackburn Buccaneer likes this.
  16. Plaka

    Plaka Brevis illi vita est

    Joined:
    Jun 19, 2010
    Oddometer:
    6,074
    Location:
    .
    gee, you mentioned every symptom except the one the OP is complaining about: smoke out the tail pipes.
    #56
    Blackburn Buccaneer likes this.
  17. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

    Joined:
    Aug 5, 2018
    Oddometer:
    162
    Location:
    North Sea rim
    Bike's at my parents' house in Hoofddorp. Some advice and help would be greatly appreciated when we finally do tackle it!

    Nope haven't done that yet, thanks for the heads up. I have a compression test lined up for when we have some more time on our hands. Don't have the equipment for a leak down, unfortunately.
    #57
  18. Blackburn Buccaneer

    Blackburn Buccaneer Been here awhile

    Joined:
    Aug 5, 2018
    Oddometer:
    162
    Location:
    North Sea rim
    Thanks for the write up, gonna keep it in mind for future reference. However the R80 is tuned up pretty well and runs great, carbs have been redone and the rubbers are all fresh. It just blows out blue-ish smoke when it gets warm, especially at idle and when giving it some throttle input while driving.
    #58
  19. bpeckm

    bpeckm Grin! Supporter

    Joined:
    Apr 2, 2008
    Oddometer:
    7,874
    Location:
    Road Island
    Re: compression test
    With the engine cold, pull the plugs and run the compression test, compare sides, they should be close to each other. Then, squirt a couple of capfuls of oil into each cylinder and run the test again. If it improves substantially, that is a good clue that the rings are culprit. If it doesn't improve anything, you could then pursue the leakdown/valve guides avenue. Valve guides, along with rings, are prime candidates for oil burning.

    :D
    #59
  20. nobbylon

    nobbylon Long timer

    Joined:
    Aug 13, 2012
    Oddometer:
    1,039
    pm me when you need a hand, I have a compression tester and free most days.
    #60
    Blackburn Buccaneer likes this.